Air intakes that centrifugally separate heavier-than-air particles from the air to be used in internal combustion engines, ventilation systems, and other apparatus that draw in air laden with debris, are known. The use of in-line filters in air delivery systems to clean the air is also, per se, known. However, air filters are subject to plugging by debris from the air passing through the filter, which eventually increases the restriction to air flow through the filter and decreases the operating performance of an associated device, such as an electronically controlled internal combustion engine being supplied with air through the filter. Frequent filter replacement and shorter service intervals may also be required, which increases the cost of operation. There is a need for an improved air cleaning system and method of making the same which combine centrifugal separation and air filtration in a manner to efficiently remove debris from debris laden air while reducing or avoiding the aforementioned problems.
A powered air cleaning system according to the invention comprises a flow path extending through the system from an air inlet to a clean air outlet. A motor-driven fan is located along the flow path to draw particulate debris laden air into the inlet and rotate it about an axis to form a rotating flow that stratifies the debris laden air with the heaviest particles in the outermost orbits of the rotating flow. An ejector port is provided for ejecting particulate debris laden air from the stratified rotating flow in the system to the environment. An air filter is located within the rotating flow and across the flow path upstream of the clean air outlet for filtering air from the innermost orbits of the stratified rotating flow. According to the disclosed example embodiments of the invention, the filter is elongated in the direction of the axis about which the debris laden air is rotated. An outer peripheral surface of the filter within the rotating flow is swept by innermost orbits of the stratified rotating flow for minimizing debris buildup on the filter.
In the example embodiments the system comprises a plurality of separable components, each defining a portion of the flow path through the system, the components being detachably connected to each other in two embodiments or located remotely, where they are separately mounted, and interconnected by an intermediate pipe assembly in a third embodiment. This modular nature of the system, with separable fan housing and air filter housing components, affords flexibility in making the system in devices with limited spaces for the system components.
A method of making a powered air cleaning system of the invention comprises forming a powered air cleaning system as a plurality of components, each defining a respective portion of a flow path through the system from an inlet to an outlet, the components including first and second components, the first component having a motor-driven fan located along the flow path to draw particulate debris laden air into the inlet and rotate it about an axis to form a rotating flow that stratifies the debris laden air with the heaviest particles in the outermost orbits of the rotating flow, and the second component having a separator-ejector chamber in the flow path downstream of the motor-driven fan, an air filter located within the separator-ejector chamber and across the flow path upstream of the outlet for filtering air from the innermost orbits of the stratified rotating flow, and an ejector port for ejecting particulate debris laden air from the stratified rotating flow in the system. The method further comprises separately mounting the first and second components in remote locations in a device requiring a supply of clean air, such as a device having a variable air flow demand, e.g. an internal combustion engine, and interconnecting the flow path through the first and second components with an intermediate pipe assembly which forms a portion of the flow path of the system.
These and other features and advantages of the present invention will become more apparent from the following description when taken in connection with the accompanying drawings, which show, for purposes of illustration only, three example embodiments in accordance with the present invention.